Conventionally, there has been video game equipment (television game equipment), or the like, in which images are displayed on a television receiver, and these images are moved in response to instructions input by input means. Most of such game equipment has utilized a stereo sound field, reproduced by stereo audio output signals output from the game equipment main unit.
When reproducing such stereo audio output signals, for instance, a pair of speakers, positioned in front of and to the right and left of the listener (game player), may for example be used; these speakers may be incorporated into the television receiver. The reproduced acoustic images are normally localized only between the two speakers used as the reproduction means, and are not localized in other directions.
Further, when a listener listens to these stereo audio output signals using stereo headphones, the acoustic image remains confined within the listener's head, and the acoustic image does not coincide with the image displayed on the television receiver.
In order to improve such acoustic image localization by headphones, a method is conceivable which uses a headphone system including hardware configured to perform signal processing capable of reproducing the audio output signals of game equipment, with a sound field sensation equivalent to that of stereo reproduction using two stereo speakers on the left and right.
However, with this method it is possible to have the acoustic image come out from the head of the listener to the outside, and to reproduce audio output signals with a sound field sensation comparable to that of stereo speakers. But similarly to the reproduction by stereo speakers, the acoustic image is localized only between two virtual speaker positions, and localizing the acoustic image in other directions is not possible; also, expensive hardware is required in order to configure virtual sound sources.
Therefore, when reproducing audio in the conventional game equipment described above, even if the output is stereo audio output signals, when audio is reproduced by game equipment, there is a disadvantage that normally an acoustic image is localized only between the two reproducing speakers, and is not localized in other directions.
Also, when listening to reproduced stereo audio output signals using stereo headphones, the acoustic image remains confined within the listener's head, and there is the problem that the acoustic image does not coincide with the image displayed on the television receiver.
Moreover, in a method which uses a headphone system comprising hardware which can perform signal processing to reproduce the audio output signals from game equipment, with a sound field sensation comparable to stereo reproduction using two stereo speakers on the right and left, it is possible to have the acoustic image come out from the listener's head, and to reproduce signals with a sound field sensation comparable to that provided by stereo speakers; but similarly to the reproduction by stereo speakers, the acoustic image is only localized between the positions of two virtual speakers, and localizing the acoustic image in other directions is not possible; moreover, there is further the problem that expensive hardware is necessary to configure the virtual sound source.